It is well known that capacitive accelerometers measure the acceleration, vibration and the inclination of objects to which they are attached. These objects typically include missiles, spacecraft, airplanes and automobiles.
In general, capacitive accelerometers change electrical capacitance in response to acceleration forces and vary the output of an energized circuit. Capacitive accelerometer systems generally include sensing elements, including capacitors, oscillators, and detection circuits.
The sensing elements include at least two parallel plate capacitors functioning in differential modes. The parallel plate capacitors generally operate in sensing circuits and alter the peak voltage generated by oscillators when the attached object undergoes acceleration.
When subject to a fixed or constant acceleration, the capacitance value is also a constant, resulting in a measurement signal proportional to uniform acceleration.
This type of accelerometer can be used in a missile or in a portion of aircraft or spacecraft navigation or guidance systems. Accordingly, the temperature in the operating environment of the accelerometer changes over a wide range. Consequently, acceleration must be measured with a high accuracy over a wide range of temperatures. This is often a difficult and inefficient process.
The disadvantages associated with current capacitive accelerometer systems have made it apparent that a new capacitive accelerometer is needed. The new accelerometer should substantially minimize temperature sensing requirements and should also improve acceleration detection accuracy. The present invention is directed to these ends.